One-Pan Tempeh with Spaghetti Squash and Dijon Mustard

Quick honesty check before we get started: this is mostly a one-pan recipe. The spaghetti squash needs real oven time on its own, so that part isn’t happening in the same skillet as the tempeh. But once the squash is roasting, everything else — searing the tempeh, building the mustard sauce, bringing it all together — happens in one pan on the stove, which is where most of the actual hands-on work is anyway.

One-pan tempeh with spaghetti squash and Dijon mustard takes crisp-seared tempeh and tosses it with roasted spaghetti squash strands in a sharp, tangy mustard pan sauce. It’s a solid weeknight option if you’re looking for something plant-based that doesn’t taste like an afterthought.

Why This Recipe Is Worth Making

Tempeh gets a bad reputation sometimes for tasting flat or bland, and that’s usually a seasoning and searing problem, not a tempeh problem. Done right — cut into cubes, seared hard until genuinely crisp — it holds up well against a sharp mustard sauce and takes on real flavor instead of just sitting there.

Spaghetti squash is also just an underused vegetable outside of the usual “swap it for pasta” framing. Here it’s playing more of a supporting role, tossed with the tempeh and sauce rather than pretending to be noodles, and it works well that way too.

What You’ll Need

• 1 medium spaghetti squash (about 3 lbs / 1.3kg), halved lengthwise and seeded
• 4 tablespoons olive oil, divided
• Salt and black pepper
• 16 oz (450g) tempeh, cut into 3/4-inch cubes
• 1 small onion, diced
• 3 cloves garlic, minced
• 3 tablespoons Dijon mustard
• 2 tablespoons whole grain mustard
• 1 cup (240ml) vegetable stock
• 1 tablespoon maple syrup
• 2 tablespoons fresh parsley, chopped, for finishing

If you don’t have both types of mustard on hand, you can use all Dijon or all whole grain — you’ll lose a little textural interest from the whole grain, but the overall flavor holds up fine either way.

How to Make One-Pan Tempeh with Spaghetti Squash and Dijon Mustard

1. Preheat the oven to 400°F (200°C). Rub the cut sides of the spaghetti squash with 1 tablespoon of the olive oil and season with salt and pepper. Place cut-side down on a baking sheet and roast for 35 to 40 minutes, until a fork easily pierces the skin and the flesh looks tender.
2. While the squash roasts, heat 2 tablespoons of the olive oil in a large skillet over medium-high heat. Add the tempeh cubes in a single layer and let them sear undisturbed for 3 minutes before flipping, then continue cooking, turning occasionally, for another 5 to 6 minutes, until deeply golden and crisp on multiple sides. Season with salt and pepper as it cooks.
3. Remove the tempeh to a plate. Add the remaining tablespoon of oil to the same pan, then add the onion, cooking for 3 to 4 minutes until softened. Add the garlic and cook for 30 seconds, until fragrant.
4. Stir in both mustards, the vegetable stock, and maple syrup. Bring to a simmer and cook for 3 to 4 minutes, until slightly thickened.
5. Once the squash is done and cool enough to handle, use a fork to scrape the flesh into strands directly into the pan with the mustard sauce.
6. Return the crisped tempeh to the pan and toss everything together over medium heat for 1 to 2 minutes, until warmed through and the squash strands are coated in the sauce.
7. Taste and adjust seasoning, finish with chopped parsley, and serve immediately.

Tips That Actually Make a Difference

Don’t rush the tempeh sear. Three minutes untouched on the first side feels like a while, but that’s what actually gets you a crisp, golden crust instead of pale, soft cubes that just sit in the sauce without much texture.

Roast the squash cut-side down, not up. It steams in its own moisture that way rather than drying out, and you get a more evenly tender result across the whole squash.

Use a fork to scrape the squash into strands right in the baking sheet or a bowl before adding it to the pan — trying to do it directly in the hot skillet is awkward and you’ll end up fighting the pan more than the squash.

Mistakes to Watch Out For

Not drying the tempeh before searing. If it’s damp from the package, it won’t crisp properly no matter how hot your pan is. Pat it dry with a towel before cutting and cooking.

Overcrowding the tempeh in the pan. If the cubes are touching, they’ll steam instead of sear. Give them real space, and work in two batches if your skillet is on the smaller side.

Undercooking the squash. If it’s still firm when you try to scrape it into strands, you’ll get short, broken pieces instead of long ones, and the texture will be more crunchy than tender. Give it the full roasting time and check with a fork before pulling it.

Adding too much mustard too fast without tasting. Mustard brands vary a lot in sharpness. Start with the amounts given, then taste and adjust rather than assuming more is automatically better.

Easy Ways to Change It Up

• Add a handful of baby spinach — stir it in during the last minute of tossing everything together; it wilts fast in the residual heat.
• Swap maple syrup for honey — if you’re not keeping this strictly vegan, honey works just as well and brings a similar rounding sweetness.
• Use chickpeas instead of tempeh — a milder option that still takes well to the mustard sauce, though you’ll lose some of the crisp texture tempeh provides.
• Add red pepper flakes — a pinch stirred into the sauce gives the whole dish a little background heat without much extra effort.

What to Serve It With

This is filling enough to work as a full meal on its own, but a simple green salad with a sharp vinaigrette is a good addition if you want something lighter alongside it. Crusty bread also works well for anyone who wants to mop up extra sauce.

If you want to stretch the meal further, serve it over a bed of cooked quinoa or farro, which soaks up the mustard sauce nicely.

Leftovers and Reheating

Store leftovers in an airtight container in the fridge for up to 4 days. The tempeh won’t stay quite as crisp once refrigerated, but the flavor holds up well.

Reheat in a skillet over medium heat for a few minutes to bring back some of the tempeh’s texture, rather than the microwave, which will leave everything softer than you’d want. If you’re in a hurry, the microwave still works fine for taste, just expect a softer bite.

Approximate Nutrition Per Serving

Values below are estimates for informational purposes only and will vary based on specific ingredients and portion sizes.

Final Thoughts

If tempeh hasn’t won you over yet, this is a fair recipe to try before giving up on it — a real sear and a sharp mustard sauce do a lot to change how it comes across. Give it a try, and don’t skip that first uninterrupted sear on the tempeh; it’s the step that actually makes the texture work.